Two studies released this week in the Archives of Ophthalmology show adults who followed a Mediterranean-style diet high in omega-3 fatty acids found in fish, nuts, and olive oil and low in the trans fats found in baked and processed foods have a much lower risk of developing the sight-robbing disease.

Age-related macular degeneration is the leading cause of blindness among older adults in the developed world. Currently, the only known risk factors for AMD are older age, genetic markers, and smoking.

In the first study, Jennifer S.L. Tan, MBBS, BE, of the University of Sydney, Australia, and colleagues examined the effects of diet on the risk of developing AMD in nearly 2,500 adults.

The participants completed a questionnaire about the foods they ate regularly. Digital photographs of the retina were taken at the start of the study and again five and 10 years later to track the development of age-related macular degeneration.

The results showed that after adjusting for other risk factors, people who ate one serving of fish per week had a 31% lower risk of early signs of AMD. Those who ate one to two servings of nuts rich in omega-3 fatty acids had a 35% lower risk.

Researchers say omega-3 fatty acids may protect the eyes by preventing the buildup of plaque in the arteries or reducing inflammation and other cell damage in the retina.

In the second study, Elaine W.-T. Chong, MD, PhD, MEpi, of the Centre for Eye Research Australia and colleagues analyzed data on 6,734 older adults over a similar period.

They found people who ate higher levels of trans fats more often found in baked goods and processed foods were more likely to develop late-stage age-related macular degeneration.

In addition, those who ate the most omega-3 fatty acids through olive oil were less likely to have AMD.

Researchers say trans fats have been shown to increase the risk of heart disease by increasing cholesterol levels and possibly spurring inflammation. These fats may also have a similar effect on the blood vessels in eyes.

In contrast, olive oil contains heart-healthy omega-3 fatty acids along with other beneficial compounds such as antioxidants and anti-inflammatory components that may help protect the blood vessels in the eyes and reduce the risk of age-related macular degeneration.